The invention relates to a wiper arm, in particular for a rear-window wiper system of a motor vehicle.
Numerous wiper arms for motor vehicle wiper systems are already known. These wiper arms have a plastic pivot part that has a wiper blade on one end. The other end is connected rotatably to a fastening part, which transmits the pendulum motion of the wiper shaft to the pivot part and thus to the wiper blade. The fastening part is embodied as a cast zinc, aluminum or plastic part.
The wiper arm of the invention having the characteristics of the main claim has the advantage that by the combination of a pivot part made of plastic with a fastening part made of sheet metal, greater torque strength is attained, and the joint between the bit and the pivot part can be achieved more easily.
In contrast to cast parts, sheet metal has hardly any creepage, and is also less expensive than cast zinc or aluminum parts.
It is especially advantageous if the pivot part, at least in the region of the second end, is shaped essentially in the form of an inverted U, and the fastening part at least partly embraces the pivot part in that region. Because the fastening part at least partly embraces the pivot part, rotary elements can be disposed on the outside of the U-shaped pivot part, instead of inside it. As a result, the pivot part is easier to make, because the number of slides in the injection-molding process, for instance, can be reduced.
It is especially advantageous if the pivot part is tapered in the region of the second end and at least one hinge pin is disposed in the tapered region. In this way, the consumption of material for the fastening part, which is intended to embrace the pivot part in this region, can be kept low. Moreover, a smooth surface between the pivot part and the fastening part can thus be achieved.
It is especially advantageous if the fastening part has a U-shaped opening pointing toward the pivot part and embracing the hinge pin on the fastening part. This makes it simple and inexpensive to achieve the rotatability between the fastening part and the pivot part.
It is moreover especially advantageous if the tapered region has a fastening element for securing a guard cap. If the guard cap is secured to the hinge pin, then the guard cap, too, can be embodied rotatably. As a result, the guard cap can protect the fastening part against environmental effects, and thus corrosion of the fastening part can be avoided.
It is also advantageous if the hinge pin is braced in the direction of the first end by bracing elements. This increases the durability of the hinge pin and thus of the fastening part, because the hinge pin is prevented from breaking off.
It is especially advantageous if the bracing elements act as stops for limiting the rotational angle, because this dual function means that no additional stops for rotational angle limitation are needed.
It is considered a further advantage if the hinge pin does not extend through the pivot part, but instead is formed only onto the outside of the lateral flanks of the U-shaped pivot part. As a result there is enough room inside the pivot part to accommodate a spring element, making it possible to do without an angle bracket or the like.
It is also advantageous if the pivot part and the fastening part are clamped together via at least one essentially straight spring element. As a result, the rotatable connection between the pivot part and the fastening part can be very simple in design.